Sometimes when we want to listen to music, we don't always want to listen to a specific artist or album. Instead, we'd rather get a good mix that caters to the mood we are currently in. You can easily ask Siri to play a specific genre for you with the help of iTunes Radio.
How to play a specific musical genre in the Music app with Siri
Press and hold the Home button to launch Siri.
Say something like "Play electronic music." or "Play alternative rock music."
The built-in Music app and iTunes Radio should start playing the genre you requested of Siri.